- Created generic ErrorPage.js with errorCode prop
- Centralized error messages in ERROR_MESSAGES dictionary
- Updated App.js to use ErrorPage for all error routes
- Updated ErrorBoundary.js to use new ErrorPage component
- Removed duplicate files: 403Page.js, 404Page.js, 500Page.js, 502Page.js, 503Page.js
- Fixed 403/404 routing: protected routes show 403, unknown routes show 404
- Error pages now vertically centered with min-height: 100vh
- Add ErrorBoundary component for React error handling
- Create animated error pages (403, 404, 500, 502, 503)
- Implement ErrorAnimation component with seven-segment display
- Add apiClient (axios) and apiFetch (fetch) wrappers with automatic error page redirects
- Migrate critical API calls to use new error handling
- Update font from Roboto to Open Sans across all components
- Remove unused CLIENT_URL from docker-compose files
- Rename 404Page.css to ErrorPage.css for consistency
- Add comprehensive ERROR_HANDLING.md documentation
